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KOMPAS.com – The universe has a speed limit and that is the speed of light.
Nothing can travel faster than light, not even the best space probes today.
So what is the speed of light?
Quoted from Live Science, Wednesday (31/5/2023) light travels at an extraordinary speed, which is 300,000 km per second, or the equivalent of more than 1 billion km/hour.
This is fast enough to circle the Earth 7.5 times in one second.
Just compare it with an ordinary passenger jet which takes more than two days to once circle the Earth. That doesn’t include stopping to refuel or layovers.
Also read: Why Are Insects Attracted to Light?
Measures the speed of light
In the early 1600s, scientist Ole Roemer was able to measure the speed of light (commonly called c) using observations from the satellites of Jupiter.
Around the turn of the 19th century, physicist James Clerk Maxwell created his theory of electromagnetism.
Light itself consists of electric and magnetic fields, so electromagnetism can describe the behavior and motion of light.
This value is 299,788 km per second, with an error margin of plus or minus 30.
However, the calculation was refined again in the 1970s by using a laser to measure the speed of light with much higher precision, leaving only an error of 0.001.
Also read: The Beauty of the Nebula’s Light from the Explosion of a Dying Star, What Is That Object?
The result is a fixed value and is used to determine the unit of length. Humans also have agreed that the speed of light is precisely 299,792,458 Km per second.
The speed of light changes
But the speed of light can change depending on what it is traveling through, for example air, water or something else. This causes the speed of light to slow down.
Interestingly, the speed of light is not proportional to the vast distances of space, which is a vacuum.
Also read: Red Ball of Light Viral Video Called Meteor and Flare Gun, Astronomer: It’s a Balloon
It takes 8 minutes for light from the Sun to reach Earth and several years for light from other nearby stars (such as Proxima Centauri) to reach our planet.
This is why astronomers use light years, or the distance that light can travel in one year, to measure vast distances in outer space.
Because of this universal speed limit, telescopes are essentially time machines.
When astronomers look at a star 500 light years away, they see light from 500 years ago.
Light from about 13 billion light years away (the equivalent of 13 billion years ago) appears in the cosmic microwave background, which is leftover radiation from the Big Bang in the early universe.
Also read: The Reflection of Light at the South Pole of Mars Isn’t Water, Likely Clay
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2023-06-01 09:00:00
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